The University of Maryland (UMD) proposes to purchase a Zeiss LSM 880 Airyscan Fast laser scanning confocal microscope under the NIH Shared Instrumentation Grant program. The instrument will be housed in the Imaging Core, which is a central shared instrumentation facility accessible to all faculty, students, and postdocs at the UMD and their collaborators, and managed by an experienced facility director. The Imaging Core provides extensive imaging services, ranging from advice on sample preparation to image acquisition and 3-D rendering. Current imaging needs at UMD range from whole organisms to interactions at the molecular level, and require high resolution visualization of fine structure. The Zeiss LSM 880 Airyscan Fast offers increased scanning speed while still retaining high sensitivity and improved resolution, all of which are important factors required for the breadth of research underway at UMD. Through extensive demonstrations, the Zeiss LSM 880 Airyscan Fast has proven to fulfill the needs of UMD's faculty. The research projects of seven major users and five minor users will greatly benefit from the microscope's state-of-the-art features, including the specialized 32-channel GaAsP Airyscan detector, which allows a 1.7x increase in x, y, and z resolution, and a 4-8x improvement in sensitivity over traditional confocal microscopes. Additional features include 6 laser lines, two standard photomultiplier detectors, an additional high-sensitivity GaAsP spectral detector, an x-y scanning stage, and the Fast module's ability to scan up to 27 frames per second at 480 x 480 pixels. A broad range of research projects will benefit from this acquisition, which will advance current knowledge on host-pathogen interactions, plasticity of the visual cortex, protein trafficking, cell- cell communication, the cellular mechanisms underlying sound localization, and the biology of extracellular RNAs. While we are only requesting funds to purchase the microscope and indispensable accessories, departmental and College support will ensure that the instrument is covered under full service contract through year 3 of the lifetime of the instrument. The user fee- based business model of the Imaging Core, as extensively demonstrated in the past, will cover maintenance needs beyond the initial 3 year period.